// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef UI_TOUCH_SELECTION_DRAG_DRAGGABLE_H_
#define UI_TOUCH_SELECTION_DRAG_DRAGGABLE_H_

#include "ui/gfx/geometry/point_f.h"
#include "ui/touch_selection/ui_touch_selection_export.h"

namespace ui {

class MotionEvent;
class TouchSelectionDraggable;

// Interface through which TouchSelectionDraggable manipulates the selection.
class UI_TOUCH_SELECTION_EXPORT TouchSelectionDraggableClient {
public:
    virtual ~TouchSelectionDraggableClient() { }
    virtual void OnDragBegin(const TouchSelectionDraggable& draggable,
        const gfx::PointF& start_position)
        = 0;
    virtual void OnDragUpdate(const TouchSelectionDraggable& draggable,
        const gfx::PointF& new_position)
        = 0;
    virtual void OnDragEnd(const TouchSelectionDraggable& draggable) = 0;
    virtual bool IsWithinTapSlop(const gfx::Vector2dF& delta) const = 0;
};

// Generic interface for entities that manipulate the selection via dragging.
class UI_TOUCH_SELECTION_EXPORT TouchSelectionDraggable {
protected:
    virtual ~TouchSelectionDraggable() { }

    // Offers a touch sequence to the draggable target. Returns true if the event
    // was consumed, in which case the caller should cease further handling.
    virtual bool WillHandleTouchEvent(const ui::MotionEvent& event) = 0;

    // Whether a drag is active OR being detected for the current touch sequence.
    virtual bool IsActive() const = 0;
};

} // namespace ui

#endif // UI_TOUCH_SELECTION_DRAG_DRAGGABLE_H_
